Plate glass is produced by continuously supplying to an apparatus a glass melt, allowing the glass melt to be flown down from the apparatus in the form of a belt, and curing by cooling during the flowing. Disk rolls act as a pair of tensile rolls and are used to hold the belt-like glass melt therebetween and forcedly send it downward.
In addition to the above-mentioned down-draw method, the plate-shaped glass can be produced by the float method, the roll-out method, the Colburn method, or the like. Glass plate produced by any of the above-mentioned methods requires an annealing process in order to remove strain by heat. A disk roll, serving as a roller, is used to convey the glass plate during this annealing process.
In general, a disk roll is obtained by fitting by insertion to a shaft (served as a rotation shaft) a plurality of disks obtained by punching a mill board (plate-like molded product, base material) in the form of a ring to obtain a roll-like stack, and applying a pressure to the entire stack through flanges provided at both ends. The outer peripheral surface of the disks functions as the conveying surface of a glass melt.
Since a disk roll conveys a glass melt for a long period of time, it is required to have not only heat resistance but also wear resistance, flexibility for protecting the glass surface from scratches, and hardness. Disk rolls containing heat-resistant inorganic fibers, mica and clay are known (Patent Documents 1 to 3). Further, a disk roll using a filler other than mica is also known (Patent Document 4).